Steam engine

ABSTRACT

A novel multi-cycle compound steam engine having novel means for providing a double use of steam and wherein the steam on opposite sides of a reciprocating piston having recti-linear movements in a cylinder may be pressure equalized and wherein the maximum amount of high pressure steam may be efficiently employed. Said piston having separate connected terminal heads with a close fitting working engagement with the cylinder wall, and wherein the body of the piston is of less diameter than the heads so that the steam chamber is provided between the heads and between the cylinder wall and the piston body, so that the steam chamber is divided into two separate compartments; and having steam compartments within the cylinder between the ends thereof and the adjacent heads of the piston; said engine being optionally usable as a double engine, or as a simple engine, and which has novel valve means as described.

United States Patent [191 Zibrun 1 [451 Sept. 18,1973

1 1 STEAM ENGINE [76] Inventor: Joseph Zibrun, 1741 W. 33rd St.,

Chicago, 111.

(22] Filed: Dec. 27, 1971 [21] Appl. No.: 212,564

[52] U.S.Cl ..9l/20,91/164,91/23l Primary ExaminerPaulE. MaslouskyAttorney-John F. Brezina et a1.

[57} ABSTRACT A novel multi-cycle compound steam engine having novelmeans for providing a double useof steam and wherein the steam onopposite sides of a reciprocating piston having recti-linear movementsin a cylinder may be pressure equalized and wherein the maximum amountof high pressure steam may be efficiently employed. Said piston havingseparate connected terminal heads with a close fitting workingengagement with the cylinder wall, and wherein the body of the pistonisof less diameter than the heads so that the steam chamber is providedbetween the heads and between the cylinder wall and the piston body, sothat the steam chamber is divided into two separate compartments; andhaving steam compartments within the cylinder between the ends thereofand the adjacent heads of the piston; said engine being optionallyusable as a double engine, or as a simple engine, and which has novelvalve means as described.

4 Claims, 16 Drawing Figures PATENTEDSEH ems $759,141

' sum 1 or 7 SHEET 2 [IF 7 PATENTEB SEN 8l975 .1 STEAM ENGINE Thisinvention relates to improvements in steam engines and more particularlyto those of the simple engine type. One object is to provide a simpleengine type having many of the advantages of the compound engine, suchas triple expansion and other multiple expansion engines, without havingmost of the disadvantages inherent in such multiple expansion types.

Among the specific advantages present in the instant engine are. theeconomical use of fuel, low maintenance, saving of steam, economicalcost of manufacture, accessibility of structural parts for repair orreplacement, and a high degree of efficiency generally, and theprovision of an engine adapted for operation at high or low speed andequally well operable under light, medium, or heavy load. A furtherobject is to provide a simple steam engine wherein a double use of thesteam may be effected, one wherein the steam upon opposite sides of thepiston withinthe cylinder may be pressure equalized, and one wherein forextra power and maximum load the maximum amount of high pressure steammay be employed, the provisions herein enumerated being manuallyselective by the operator and dependent upon the nature of the work inhand.

A still further object is to provide a simple steam engine having acylinder provided with a piston having rectilinear movement therein,said piston provided with terminal heads having close fitting workingengagement with the cylinder wall, the body of the piston being ofmaterially less diameter than the heads so that a steam chamber isformed between the cylinder wall and piston body between said heads,piston rings being provided within the cylinder about the piston bodywhich divide this steam chamber into two separate compartments, thesecompartments receiving and exhausting steam during the normal operationof the piston, steam compartments being also fonned within the cylinderbetween the ends thereof and the adjacent heads of the piston.

Other advantages and ob jects of my engine are:

a. to provide a novel, multi-cycle compact compound steam engine whichis unique in design inwhich the moving partsare relatively easilyaccessible for repairs or servicing; which can beused either as a simpleene. and which includes two steam control valves, and only one of whichvalves may be used at one time depending on the requirements of thework.

Other objects, novel features and advantages of ar rangement,construction and design comprehended by the invention are hereinaftermore fully pointed out or made apparent from the following descriptionof a preferred embodiment as illustrated in the accompanying drawingswherein like reference characters denote corresponding parts throughout.

DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a side view of a steam engine, with parts broken away,embodying the features of the instant invention.

FIG. 2 is a top plan view of the engine of FIG. 1.

FIG. 3 is a longitudinal vertical central sectional view through FIG. 2on the line 3-3.

FIG. 4 is a horizontal cross sectional view through FIG. 3 on the line4-4.

' FIG. 5 is a vertical cross sectional view through FIG. 3 on the line5-5.

FIG. 6 is'a view similar to FIG. 5 but on the line 66 of FIG. 3.

FIGS. 7, 8, and 9 are vertical cross sectional views taken respectivelyon the line 7--7, 8-8, and 9-9 of FIG. 3.

FIG. 10 is a view in side elevation of the slide valve employed.

FIGS. 11 and 12 are views similar to FIG. 3 but with certain parts inaltered positions.

gine or a double engine using only one piston and one I cylinder; andwhich includes a novel and modified piston valve;

b. which is selectively changeable so as to change of operation from onesingle engine to a double engine according to work requirements; Y

c. to provide a novel engine which has structural means whereby thesteam enters at the approximate center of the cylinder and may beexhausted at either end of the cylinder, and in which the piston mountedin the cylinder provides two separate and independent steam chambers,each working independently to supply steam to the same piston which hasfour power impulses to each revolution as a double engine or as acompound engine, and in which there are two power impulses when operatedas a normal engine,

d. which includes 6 manually operated valves mounted to open and closetheir respective steam passages, said valves being manually selectivelyoperable depending on the requirements of the work being performed,

FIG. 13 is a view in elevation of a valve casing employed.

FIG. 14 is an enlarged view in section of the cylinder, without thepiston, and the steam by-pass structure associated therewith.

FIG. 15 is a view similar to FIG. 14 but with the valves in an alteredor open position, and,

FIG. 16 is a longitudinal central sectional view, partly broken away, onthe line l616 of FIG. 14.

As disclosed in the drawings the reference numeral 1 denotes the oblongsteam chest having a cover plate 2, front end plate 4 and rear end plate5, said steam chest having atop its cover plate and approximatelycentrally thereof the relatively small steam dome 6 having a base flange7 secured to said cover plate by screw bolts 8, thedome in its crownreceiving the nut 9 securing the steam pipe 10 connected by valvedcoupling 11 to the steam pipe 12 leading to the boiler (not shown). Thevalved coupling 11 is provided with a handle 13 for controlling theadmission of live steam from the pipe 12 to pipe 10 which communicateswith the dome.

Communicating with a port 14 in the steam chest cover 2 is the pipe 15connected by elbow 16 to a pipe 17 connected by elbow 18 with steam pipe19 that is connected by three-way coupling 20 to steam pipes 21, 22, thepipe 21 connected by T-coupling 23 connected to, pipe 24 that registerswith the port 25 in cover 2, the pipes 15, 24 arranged upon oppositesides of the steam dome and adjacent opposite ends of the steam chest,the pipe 22 being provided with a control valve 26 and leading to theboiler. Also received atop the cover plate 2.at the front and rear endsthereof respectively are the sills 27, 28, each secured in place bybolts 29, each receiving a steam discharge pipe 30 registering with aport 31 in registry with a terminal port 32 at each end of the steamchest, each pipe 30 being connected by an elbow 33 conneced a steam pipe34, one at each end of the cover plate 2, to a steam condenser, ifdesired (not shown), or communicating with the atmosphere.

The steam chest 1 includes the base plate 35 integral with the sides 36,37, said plate and sides secured to the front and rear plates by thebolts 38'.- Spaced from the sides 36, 37, integral with the base 35 andrising therefrom to the cover plate 2 and extending from the front tothe rear plates 4, 5 is the core 340 formed longitudinally in its lowerapproximately central portion with a cylindrical bore 38a extending fromend to end of a diameter substantially two-fifths that of the core inwhich is snugly received the cylindrical valve chamber 39, the ends ofwhich abut the end plates 4, 5 and are closed by said plates, said valvechamber being formed at each end with longitudinally extending duplicateterminal ports 40, 40a and inwardly from each set of terminal ports witha plurality of duplicate ports 41, 41a somewhat smaller than the ports40, 40a, and arranged in a circle and preferably in staggered relationto ports 40, 40a, and inwardly from ports 41, 41a with a plurality ofduplicate ports 42, 42 a similar to ports 41, 41a in size andarrangement, and inwardly from each ring of ports 42, 420 with arelatively large imperforate portion 43 and inwardly from each with twinspaced rings of duplicate oppositely disposed ports 44, 44a.

Between the sets of twin rings is a central ring of somewhat elongatedports 45. The core 34a is spaced from the end plates to form duplicatefront and rear ports 46, 47 that register with the smaller ports 32 inthe cover plate and that extend around and slightly below the valvechamber 39 and register with the terminal ports 40, 40a of said chamberand spaced inwardly from said ports 46, 47 with forward and rear ports48, 49 that extend through the base 35 and about and slightly above thevalve chamber but not through the core top face but that register withthe valve chamber ports 41, 41a disposed near opposite ends of thatchamber. Separated from the closed upper terminals of the ports 48, 49and spaced inwardly from the front and rear core ports 46, 47 are thelarge steam chamber portions 50, 51 much larger than and that registerrespectively with the cover plate ports .25, 14, said chamber portions50, 51 being formed respectively with contracted portions 52, 53 thatextend to and about and slightly below the valve chamber 39 and thatregister with the ports 42, 42a thereof, the ports 52 registering withthe valve chamber ports 42 and the ports 53 registering with the valvechamber ports 42a.

Spaced inwardly from the large steam chamber portions 50, 51 are themedium size ports 54, 55 that extend from the top face of the core toand about the valve chamber and slightly therebelow and which ports 54,55 register respectively with the rings of valve chamber ports 44a, 44,said ports 54, 55 also registering respectively with the cover plateports 56, 57 that open into the steam dome 6. Spaced inwardly from theports 54, 55 are the core ports 58, 59 of medium size, the inner closedterminals thereof disposed slightly above the valve chamber, the portsextending about the adjacent rings of valve chamber ports 44a, 44 andregistering therewith, the lower ends of said ports 58, 59 beinginclined toward each other as they pass through the base 35. Disposedinwardly of the ports 54, 55 and slightly above the inner ends of theports 58, 59 is the centrally disposed steam chamber portion 60 closedby the cover plate 2.

Steam chamber portion is formed with a contracted extension 61, thejuncture of the portions 60, 61 defining the seat of the check valve 62,the stem 63 of which is formed with a steam passageway 64, said stemoperatively received in the guide sleeve 65 operatively supported in thecover plate 2, said stem 63 withinsleeve 65 being received upon one endof the expansion coil spring 66. Operatively received within the valvechamber 39 is the valve 67 shown per se in FIG.

10 and comprising a stem 68 of somewhat greater length than the chamberand extending through the front steam chest wall 4 and through thestuffing box 69 and connected by the crosshead 71 and pin 72 to theconnecting rod 73 connected to eccentric 75 connected to the shaft 76 ofthe fly wheel 77 operatively arranged upon the supports 78. Fast upon orintegral with the valve stem 68 are the spaced valve units of a commondiameter and of predetermined thicknesses and spacings upon the valvestem for effective cooperation in closing and opening the several ringsof ports in the valve chamber in predetermined manner, the terminalvalve units 80, 800 being of a common thickness and and adapted to open,partially open and close the terminal ports 40, 40a and adjacent ports41, 41a, 42, 42a, the duplicate valve units 81, 81a of a lesser commonthickness adapted for like service in connection with the rings of ports44a, and the innermost or adjacent valve units 82, 82a for cooperationwith the more closely associated rings of ports 44 and with the centralports 45, as the valve is moved axially within the valve chamber.

Referring again to the base plate 35, same is flush with and receivedupon the top wall of the cylinder 83 arranged upon the hollow base 84supported upon the floor or base plate 85, the cylinder having anexterior substantially square in cross section and having secured toopposite lateral faces the rectangular plates 86, 87, the top edges orfaces of which are flush with the top outer face of the cylinder, saidplates extending longitudinally of the cylinder from end to end and of adepth substantially one-half that of the cylinder, the cylinder boreclosed at one end by the front head 88 having a central perforation 89and by a rear head 90 formed with a centrally disposed inner faceclearance recess 91.

Substantially the forward half of the cylinder wall is recessed upon itsinner face to receive the sleeve 92 the wall of which is of the samethickness as the depth of said recess and coextensive therewith, thejuncture of the recessed and non-recessed portions of the cylinder wallinner face defined by an annular rib 93 integral with the cylinder walland disposed inwardly slightly extending completely thereabout.Contiguous to the rib 93 and fast to the inner face of the sleeve 92 isthe band 94 that carries the twin piston rings 95, 96 in contiguity, thethickness of a piston ring and the band being equal to the depth of thering 93 inside the cylinder bore, the diameter of the cylinder bore uponopposite sides of the rib and piston rings, with band 94 being the same.

Received within the cylinder is the piston 97 having terminal heads 98,99, the body of the piston being of materially smaller diameter than thecylinder bore and extending through the piston rings and rib and havinga close fitting steam-tight operative engagement therewith,'the heads ofthe piston having a like operative engagement with the cylinder wall inconventional manner, the piston having the piston rod 100 extendingthroughout and secured thereto at one end by the nut 101 that, as thepiston'operates, moves into and out of the clearance 91, the piston rod100 passing through the plate perforation 89 and connected by crosshead102 to the connecting rod 103 by pin 104, the connecting rod secured bypin 104a to the crank 105. The plates 86, 87 are each formed withpassageways 107, 108 tangential to the cylinder wall and each extendingfrom points adjacent the cylinder ends to points beyond the center ofthe cylinder, the passageway 107 adapted to register with ports 109,110, in the cylinder wall adjacent one end and the center of thecylinder, said ports and passageway being connected respectively byvalves 111, 112, valve 111 being provided with handle 113 and valve 112provided with handle 114, the several valve handles being supported inprojections 114a of the steam chest side walls. The plates 86, 87 areformed further with ports 121, 122 arranged upon opposite sides of thepiston rings and adapted to be opened and closed by the said valves 112,118.

In FIG. 14 the valve 112 is in position to close one end of thepassageway 107 and the valve 111 is in posi tion to close the oppositeend of the said passageway, the valve 112 opening the port 121 to port110 in the cylinder. In this figure the valves 117, 118 are in positionto close the ends of the passageway 108 and the port 115. The valve 118also opens the port 116 in the cylinder to port 122 in the plate 87. Theports 121, 122 respectively receive elbows 123, 124, the latterconnected by pipe 125 to elbow 126 connected to pipe 127 which isconnected by elbow 128 connected to pipe 129 which is engaged by elbow123.

It will be noted that the steam pipes 12 and 22 both lead to the steamboiler. Pipe 12 is provided with steam valve 13, while steam pipe 22 isprovided with control valve 26 so that steam from either pipe 12 or 22may be received in the steam chest. Under a medium load the valve 26 isopened, admitting steam from the boiler through the pipe 22, T-coupling23, pipe 24 into the steam chest compartment 50, through the contractedportion 52 about the valve chamber 39 and through ports 42 thereof andbetween the valve units 80, 81, where it temporarily remains. As thevalve 26 is open the steam also passes through steam pipe 19, pipe 17,pipe into the steam chest compartment 51, through port 53, through valveports 42a, between the valve units 80a, 81a where it remainstemporarily. The steam chest is now full of high pressure steam.Referring now to FIG. 14 the valves 112, 118 are open setting upequalized pressure upon both sides of the piston rings 7 within thecylinder. As shown in FIG. 3 the valve 67 is in neutral position withthe terminal ports 48, 49 in the steam chest closed by the terminalvalve .units 80, 80a within the valve chamber, and the central steamchest ports 58, 59 also closed by the valve units 82, 82a. The fly wheel77 is now moved manually to cause the valve 67 to move aboutfive-eighths inches to the extreme end of its inner stroke causing thevalve unit 80a to uncover ports 41a in the valve chamber and admit steamtherethrough and through terminal port 49 into the space between therear piston head 99 and the rear cylinder head. The piston is now inposition to be acted upon by this steam which in expanding forces thepiston to the right.

When the piston, FIG. 3, has moved to the right to dotted line position,the valve 67 has moved to the right sufficiently to close terminal port49 cutting off the steam supply. The piston continues in this directionto complete its stroke to the right which is a position contiguous tothe rib 93. During this piston movement the valve has moved to the rightuncovering valve chamber ports 41a permitting this steam to exhaust frombetween .the piston head 99 and rear cylinder head, the exhaust steampassing through chamber ports 41a and a and ports 47 and out throughsteam pipe 30 into the atmosphere or to a condenser. As the pistonreaches the limit of its outward movement the valve is still moving tothe right or outwardly uncovering steam chest port 48 admitting steaminto the cylinder against the outer face of the piston head 98 causingthe piston to travel to the left again, and by the time the said head 98has travelled again to dotted line position, FIG. 3, the valve 67 hasmoved to the left sufficiently to again close the port 48 cutting offthe live steam intake; the piston continues to the left with the steamaccelerating its movement through expansion until the stroke iscomplete.

The following is the follow through for a light to a medium load: Livesteam from the boiler flows through pipe 12 when valve 11 is open (pipe22 being closed) into the steam dome 6 and out through steam chest coverports 56, 57 into the steam chest and through the open remote valvechamber ports 44, 440 into the valve chamber and around and below same,the steam filling the spaces or chambers between the valves 81, 82, 81a,82a and being. therein temporarily confined, the valve 67 being inneutral position, FIG. 3. When the fly wheel is manually moved aspreviously described the valve 67 moves five-eighths inches to the left,the piston moving slightly to the right from FIG. 3 position, causingvalve 82 to uncover port 59 registering with port 130 in sleeve 92, saidport 130 registering with the space 131 between the piston body and theinner periphery of the sleeve 92. The steam in space 131 exerts pressureupon the left side of the piston head 98 causing the piston to move tothe right, the space 131 increasing in extent as the piston movesforwardly.

The valve 67 is now moving to the right with the piston, the valvehaving started this movement almost simultaneously with the piston. Whenthe piston has traveled to the right hand dotted line position, thevalve 67, unit 82, has moved sufficiently to the right to close the port59 and no more steam is then admitted to the space 131. the

The steam expansion in space 131 forces the piston to complete its righthand stroke, the valve 67 continuing to the right almost to its farthestright hand position also. This valve movement causes valve unit 82 touncover port 59 and one ring of ports 44 permittingthe steam in space131 to exhaust through ports 59, 44 into the valve chamber between units82, 82a. From this chamber it passes'through valve chamber ports 45opening check valve 62 and passing into steam chamber 60 and through theopen spaces about the core into the steam chambers 50, 51, the steamchambers 50, 51, 60 having plate 2 as cover. These chambers are nowfilled with exhaust steam.

Just before the valve 67 reaches its extreme right hand position, thevalve unit 82a uncovers the port 58 and permits high pressure steam topass from the dome 6 through port 56, port 54, outer ring Ma of ports inchamber 39, all around the valve chamber and out through the inner ring44a of valve chamber ports,

through port 58, through port 132 in the cylinder wall contiguous to thesaid rib 93, said port 132 opening into a steam space 133 between thepiston body 97 and the cylinder wall and abutting the rib 93 andcylinder head 99. The high pressure steam entering the space 133 forcesthe piston to the left and at the same time the exhaust steam stored inchambers 50, 51, 60 passes through port 54, through valve chamber ports42, through ports 41, through port 48 in register with port 134 in thecylinder wall, through port 135 in sleeve 92 and into the cylinderbetween the head 88 and the piston head 98 and acts against the latter,thus at the same time the high pressure steam is acting against thepiston head 99 in steam space 133 thus providing two forces actingsimultaneously upon the piston in a common direction. This continuesuntil the piston reaches the dotted line position in FIG. 3. The valve67 has now travelled far enough to the left to cover the ports 58, 48.No more steam now enters the cylinder between the piston head 98 and thecylinder head 88 nor the steam space 133. The steam in both spacescontinues to expand forcing the piston to complete its stroke to theleft. At this time the valve 67 has moved to the left sufficiently touncover port 58 and permit the exhaust to pass through the innermostleft ring 440 of valve chamber ports into the ring 45 of ports, raisingthe check valve 62 and passing into the chambers 50, 51, 60 where itagain temporarily remains. Valve unit 80 has now moved to the left touncover port 48, ports 40, 46, 32 and out through pipe 30 to theatmosphere or to a condenser. The valve 67 has now moved almost to theend ofits left stroke into a position to permit high pressure steam fromthe dome 6 to pass through the steam passageways, in a manner aspreviously described, into the steam space 131 forcing the piston to theright.

At the same time the steam in chambers 50, 51, 60 is passing throughport 53, valve chamber ports 42a, 41a, 49, cylinder port 136 into thespace 136a between the cylinder head 90 and the piston head 99cooperating to force the piston to the right. As the piston travels tothe dotted line position, FIG. 3, the valve 67 has moved sufficiently tothe right to shut off more steam from entering the cylinder from thesteam chest and steam dome, the steam expanding in the cylinder causingthe piston to complete its stroke to the right. As the piston completesthis stroke, the valve following, the valve uncovers the ring 41a ofvalve chamber ports permitting the steam in the cylinder to exhaust toand through the pipe 30 into the atmosphere or condenser. With theengine under heavy to extra heavy load the operation is as follows: Inthis case the mechanism disclosed in FIGS. 14 and 15 is brought intoplay. The mechanism is shown in FIG. 15 in open or operative position.High pressure steam, valve 26, FIG. 3 being closed, flows from pipe 12into the steam dome and the operation is that described with referenceto the description for light to medium load previously recited. As shownin FIG. 15, the valve 118 permits steam to pass from the cylinderthrough port 116 into passageway 108, and valve 117 permits the steam tocontinue through port 115 into the cylinder upon the opposite side ofthe piston ring. This steam now passes into the steam space 1360 betweenthe left face of piston head 99 and the cylinder head 90 forcing thepiston to the right, some of the steam through the port 136, throughport 49, through ring of ports 41a, 42a, through port 53 into the steamchest intercommunicating chambers 50,

51, 60 where it temporarily remains. A portion of the steam also movesthe piston to the dotted line position, FIG. 3. Valve 67 has now movedsufficiently to the right from extreme left position to close port 59 sothat high pressure steam may not continue to be supplied from the steamdome through the steam chest into the cylinder. Expansion steam withinthe cylinder to the left of the piston head 99 and steam within thecylinder to the left of piston head 98 will cause the piston to completeits stroke to the right. The valve will now have opened passageways136a, 136, 49 to exhaust the steam and through valve chamber ports 40a,passageways 47, 32 and pipe 30 into the atmosphere or condenser.

At the same time the steam in the cylinder between the piston ring andpiston head 98 will exhaust through port 116, passageway 108, port 115,FIG. 15 position, into passageway 136a and finally out through pipe 30as just described. The piston is now at the extreme right hand end ofits stroke. The valve 67 continues to the right to uncover port 58 tothe left of the piston ring and permit steam from the steam dome to passthrough ports 56, 57, 54, 55, through remote rings of valve chamberports 44, 44a, through port 58 into the cylinder between the piston ringand the right face of piston head 99, the piston position now beingabout that shown in FIG. 11. At the same time, as in FIG. 15, the steamfrom the cylinder at the left of the piston ring passes through portinto passageway 107 into port 109 and back into the cylinder to theright of the piston head 98. There is now high pressure steam effectiveupon the right hand side of both piston heads. This forces the piston tothe left into dotted line position, FIG. 3. The valve 67 has now movedto the left to close port 58 allowing no more steam from the dome toenter the cylinder. This steam continues to expand thus forcing thepiston to extreme left hand position.

The valve continues to the left uncovering ports 134, 135, 110,passageway 107, port 109 into the cylinder between cylinder head 88 andpiston head 98, the steam exhausting from the sleeve and cylinder ports135, 134 through port 48, ring of valve chamber ports 41, 40, ports d6,32, 31 and out through pipe 30. It will be noted that the check valve 62normally remains closed so that with the engine running as justdescribed, the steam from chambers 50, 51, 60 will not escape throughvalve chamber ports 45 and out through other valve ports and finallythrough ports 110, 116, 109, l 15 to the atmosphere.

While the foregoing specification sets forth the invention in specificterms, it is to be understood that numerous changes in the size ofmaterials may be resorted to without departing from the spirit and scopeof the invention as claimed hereinafter, and it is contemplated thatvarious changes may be made in the embodiment of the invention hereinspecifically described.

I claim:

1. In a steam engine, cylinder means defining internal cylindricalsurface means, piston means reciprocably movable in said cylinder meansand including first and second end portions having external cylindricalsurfaces of the same diameter in sealing engagement with said internalcylindrical surface means and including an intermediate reduced diameterportion between said first and second end portions and defining anexternal cylindrical surface in concentric relation to said cylindricalsurface means, annular means projecting inwardly from a central portionof said cylinder means into sealing engagement with said externalcylindrical surface of said intermediate reduced diameter portion ofsaid piston means to define a first space between said first end portionof said piston means and said annular means and a second space betweensaid second end portion of said piston means and said annular means,forward wall means closing one end of said cylinder means to define athird space between said forward wall means and said first end portionof said piston means, reciprocable valve means operable between firstand second positions in synchronized relation to reciprocable movementof said piston means, said reciprocable valve means including firstmeans operable in said first position of said reciprocable valve meansfor introducing high pressure steam into said first space to move saidpiston in a forward direction toward said forward wall means andincluding second means operable in said second position of saidreciprocable valve means to introduce high pressure steam into saidsecond space to move said piston in a reverse direction away from saidwall means, and reverse direction compound action control valve meansarranged to be opened for flow of steam from said second space to saidthird space when said reciprocable valve means is in said secondposition to obtain a compound action in said reverse direction.

2. In a steam engine as defined in claim 1, said reciprocable valvemeans further including third means for introducing high pressure steaminto said third space in said second position of said reciprocable valvemeans to obtain a double action, reverse direction double action controlvalve means for controlling said introduction of high pressure steamthrough said third means of said reciprocable valve means, said reversedirection compound action control valve means being closed when saidreverse direction double action control valve means is open.

3. In a steam engine as defined in claim 1, rearward wall means closingthe opposite end of said cylinder means to define a fourth space betweensaid rearward wall means and said second end portion of said pistonmeans, and forward direction compound action control valve meansarranged to be opened for flow of steam from said first space to saidfourth space when said reciprocable valve means is in said firstposition to obtain a compound action in said forward direction.

4. In a steam engine as defined in claim 3, said reciprocable valvemeans further including fourth means for introducing high pressure steaminto said fourth space in said first position of said reciprocable valvemeans to obtain a double action in said forward direction, and forwarddirection double action control valve means for controlling saidintroduction of high pressure steam through said fourth means of saidreciprocable valve means, said forward direction compound action controlvalve means being closed when said forward direction double actioncontrol valve means is open.

* a: is =r=

1. In a steam engine, cylinder means defining internal cylindricalsurface means, piston means reciprocably movable in said cylinder meansand including first and second end portions having external cylindricalsurfaces of the same diameter in sealing engagement with said internalcylindrical surface means and including an intermediate reduced diameterportion between said first and second end portions and defining anexternal cylindrical surface in concentric relation to said cylindricalsurface means, annular means projecting inwardly from a central portionof said cylinder means into sealing engagement with said externalcylindrical surface of said intermediate reduced diameter portion ofsaid piston means to define a first space between said first end portionof said piston means and said annular means and a second space betweensaid second end portion of said piston means and said annular means,forward wall means closing one end of said cylinder means to define athird space between said forward wall means and said first end portionof said piston means, reciprocable valve means operable between firstand second positions in synchronized relation to reciprocable movementof said piston means, said reciprocable valve means including firstmeans operable in said first position of said reciprocable valve meansfor introducing high pressure steam into said first space to move saidpiston in a forward direction toward said forward wall means andincluding second means operable in said second position of saidreciprocable valve means to introduce high pressure steam into saidsecond space to move said piston in a reverse direction away from saidwall means, and reverse direction compound action control valve meansarranged to be opened for flow of steam from said second space to saidthird space when said reciprocable valve means is in said secondposition to obtain a compound action in said reverse direction.
 2. In asteam engine as defined in claim 1, said reciprocable valve meansfurther including third means for introducing high pressure steam intosaid third space in said second position of said reciprocable valvemeans to obtain a double action, reverse direction double action controlvalve means for controlling said introduction of high pressure steamthrough said third means of said reciprocable valve means, said reversedirection compound action control valve means being closed when saidreverse direction double action control valve means is open.
 3. In asteam engine as defined in claim 1, rearward wall means closing theopposite end of said cylinder means to define a fourth space betweensaid rearward wall means and said second end portion of said pistonmeans, and forward direction compound action control valve meansarranged to be opened for flow of steam from said first space to saidfourth space when said reciprocable valve means is in said firstposition to obtain a compound action in said forward direction.
 4. In asteam engine as defined in claim 3, said reciprocable valve meansfurther including fourth means for introducing high pressure steam intosaid fourth space in said first position of said reciprocable valvemeans to obtain a double action in said forward direction, and forwarddirection double action control valve means For controlling saidintroduction of high pressure steam through said fourth means of saidreciprocable valve means, said forward direction compound action controlvalve means being closed when said forward direction double actioncontrol valve means is open.